1. Field of the Invention
The invention relates to a method for operating an internal combustion engine and to a control device for carrying out the method.
2. Description of the Related Art
DE 10 2007 046 655 A1 discloses an internal combustion engine that comprises a cylinder row of multiple cylinders. Each cylinder of the cylinder row has multiple outlet valves for exhaust gas so that the cylinders of the cylinder row are coupled by first outlet valves and a first exhaust-gas duct to a first turbine of a first exhaust-gas turbocharger, and by second outlet valves and a second outlet duct to a turbine of a second exhaust-gas turbocharger. A compressor of the first exhaust-gas turbocharger is coupled to the cylinders of the cylinder row by a first charge-air line, and a compressor of the second exhaust-gas turbocharger is coupled to the cylinders of the cylinder row by a second charge-air line. Exhaust gas exiting the cylinders of the internal combustion engine is conducted either exclusively via the first exhaust-gas turbocharger or both via the first and second exhaust-gas turbochargers. The two exhaust-gas turbochargers are connected in parallel with one another. The exhaust gas exits the cylinders exclusively via the first outlet valves of the cylinders when the exhaust gas is conducted exclusively via the turbine of the first exhaust-gas turbocharger. By contrast, the exhaust gas can exit the cylinders of the cylinder row via both outlet valves in parallel when the exhaust gas is conducted in parallel via the turbines of both exhaust-gas turbochargers. Such an internal combustion engine is referred to as an internal combustion engine with sequential supercharging.
Internal combustion engines with sequential supercharging are known from DE 10 2007 046 655 A1, DE 10 2007 046 656 A1 and DE 10 2008 036 308 B4. However, there is a demand for improving the operation of such an internal combustion engine in to utilize the sequential supercharging optimally.
It is an object of the invention to provide a novel method for operating an internal combustion engine, and a control device for carrying out the method.